Live or real-time yield monitoring during crop harvesting is known in the art. One type of commercially available yield monitor uses an impact-type mass flow sensor such as that disclosed in U.S. Pat. No. 5,343,761, which is hereby incorporated herein in its entirety by reference. Although such monitors are generally capable of indicating the relative rate of mass flow in the combine during harvesting, they are known to be substantially inaccurate. As the interest and market investment in site-specific farming practices (e.g., variable rate planting and crop input applications) has increased, the need for accurate yield measurements (e.g., to generate accurate spatial yield maps by associating yield measurements with GPS-tracked locations) has become more significant.
As such, there is a need for apparatus, systems and methods of accurately measuring mass flow rate of grain while harvesting.